Wind spilling driver direction sign for highways

ABSTRACT

For displaying official traffic and roadway messages to oncoming motorists, a driver information sign is provided for disposition in proximate generally perpendicular relation to a vehicular traffic lane and comprises a series of parallel letter supports formed by aluminum extrusions cut to length and spaced apart by stacks of intervening spacers bound together by tie rods to form a sturdy and lightweight assembly. The letter supports have grooved frontal edges defining a message face wherein one or more rows of message letters having individual structural integrity span adjacent letter supports and are attached thereto by screws. The spacers and letter supports form wind tunnels that minimize wind forces on the sign by passing wind freely through the message face and the sign structure. Laterally deflected excursions of the letter supports block vision through the sign and define a visually continuous background surface for lettering in the message face. Anchor bolt receiving grooves formed in the rear edges of a dispersed plurality of the letter supports receive sign supporting forces that can be widely dispersed to avoid stress concentrations and patterned to accommodate a wide variety of supporting structures. If desired, the letter supports can be shaped along both edges for attachment of letter characters in two message faces on opposite sides of the sign.

United States Patent 1 Dunne 1 Oct. 30, W73

[ WIND SPILLING DRIVER DIRECTION SIGN FOR HIGHWAYS Samuel B. Dunne, P.O. Box 200, Amboy, Ill.

[22] Filed: Jan. 27,1972

[21] Appl. No.: 221,210

[76] Inventor:

Primary Examiner-Robert W. Michell Assistant Examiner-John F. Pitrelli Att0rneyMarshall A. Burmeister et al.

[57] ABSTRACT For displaying official traffic and roadway messages to oncoming motorists, a driver information sign is provided for disposition in proximate generally perpendicular relation to a vehicular traffic lane and comprises a series of parallel letter supports formed by aluminum extrusions cut to length and spaced apart by stacks of intervening spacers bound together by tie rods to form a sturdy and lightweight assembly. The letter supports have grooved frontal edges defining a message face wherein one or more rows of message letters having individual structural integrity span adjacent letter supports and are attached thereto by screws. The spacers and letter supports form wind tunnels that minimize wind forces on the sign by passing windfreely through the message face and the sign structure. Laterally deflected excursions of the letter supports block vision through the sign and define a visually continuous background surface for lettering in the message face. Anchor bolt receiving grooves formed in the rear edges of a dispersed plurality of the letter supports receive sign supporting forces that can be widely dispersed to avoid stress concentrations and patterned to accommodate a wide variety of supporting structures. If desired, the letter supports can be shaped along both edges for attachment of letter characters in two message faces on opposite sides of the sign.

6 Claims, 8 Drawing Figures PAIENIEUncfao 191s 3,768,187 sum 1 ur 3;

32/ HXQN ELL 1 20 NEXT EXHT WIND SPILLING DRIVER DIRECTION SIGN FOR HIGHWAYS wording be displayed in such manner that drivers possessed of only ordinary vision and driving skill are able to read and comprehend the message at a glance while travelling at highway speeds and concentrating primarily on avoiding collisions-with other vehicles.

To meet these stringent requisites of readability under outdoor traffic conditions, which place a high premium on avoidance of either error in reading the essential messages displayed or undue distraction of the motorists attention from the road and traffic, the lettering symbols and diagrams of such driver information must be large. In particular, the lettering must be large enough to be easily read from a distance away that is sufficient to allow motorists travelling at highway speeds adequate time to perceive and read the message. Moreover, it is essential to accurate reading of the message by the motorist that the lettering be distinctive and that it be displayed against a background that accentuates the visibility of the lettering and avoids confusion of the letter characters with the sign support structure or any other structure, spaces or colors that may be situated behind the letters. Finally, the display must retain its distinctiveness and legibility outdoors in all kinds of weather.

These requisites of functional suitability for this type of highway service have been met in a general way by roadway information display signs of conventional design.However, conventional signs designed for installation to inform the highway motorist, as indicated, have suffered characteristically a number of inherent shortthis invention and which areovercome bythis-invention.

characteristically, conventional roadway information display signs of this character. which have gained acceptance for installation along modern superhighways, have had, because of the need to display messages in large distinctive lettering and because of the concomitant need to provide an acceptable background surface for such lettering, a very extensive sail area that is ,unavoidability exposed and subjected to very large, irregular. and sometimes vibratory wind loads. Theheavy and most irregular wind loads on such signs have greatly'increased the load that must be sustained with absolute assurance against failure by the supporting structure for such signs. The location of the signs is such that a structural failure of the support structure could topple a sign into the path of a stream of vehicles with disastrous consequences. Moreover, it is highly desirable from the aesthetic standpoint that the sign support structure itself be simplified in design and rendered as visually pleasing as possible.

Heretofore, approaches to meeting the requirements for pleasing appearance of highway sign support structure while satisfying the strength requirements essential to sustain, in addition to the weight of the sign structure comings and disadvantages which are the concernof itself, the heavy and irregular wind loads on conventional signs have added heavily to the cost of conventional signs and support structure for conventional signs and have lead to compromises in most desirable standards of appearance for conventional signs and support structures.

One object of this invention is to provide a new and improved roadway information sign structure which affords many worthwhile advantages both by way of manufacture and use, especially in the described service of displaying to oncoming motorists essential roadway and traffic messages.

A further object is to provide for mounting in proximate relation to a highway traffic lane a new and improved sign that displays messages in large readable lettering conspicuously set off against a visually solid background surface, while at the same time drastically reducing the wind resistance of the sign structure with consequent drastic reductions in the wind loading on the sign structure as compared with conventional signs affording similar message display areas.

A further object is to provide for outdoor use a new and improved roadway information display sign which provides a visually solid background surface for the conspicuous display of large message lettering while at the same time providing for the passage of wind and strong air currents through the message display face of the sign and through the sign itself to the end that differential air pressure on the sign is reduced and windloadings on the sign are drastically minimized.

A further object is to provide a new and improved traffic information sign of I the character recited in which the message face on which large lettering is conspicously displayed against a visually solid background is rendered highly permeable to a generally free flow of wind through the message face, the message face and the sign structure itself-being rendered permeable to the free passage of .w ind therethrough by multitudinous wind tunnels formed in the sign structure and presenting a cumulative front area in the message face equal to a major. fraction of the area of the message display face.

A further object is to provide a new and improved traffic information display sign of the character recited which is light in weight and strongly resistant to torque and force loadings in all directions and which provides for a free flow of wind through the sign structure with a consequent minimization of wind loading on the sign, while at the same time maintaining behind the lettering of the message displayed a visually solid background surface.

A further object is to provide a new and improved roadway traffic message display sign of the character recited which greatly minimizes, in relation to the mes? sage display area afforded by the sign, the wind loading of the sign with a corresponding minimization of the strength requirements of the structure used to support the sign in proximate relation to a highway traffic lane.

A further object is to provide an improved traffic and roadway message display sign as recited'in the preceding objects which, by virtue of its inherent strength through design, its inherent light weight and its inherently low resistance to wind with consequent low wind loadings, is well suited to be made larger in overall size to effectively mask associated support structure for the sign and present to the viewing motorist an aesthetically enhanced appearance of the overall structure including the support structure.

A further object is to provide an improved sign structure as recited in the preceding objects having inherent strength through design which makes practical and feasible the construction of the sign from noncorrosive light metals, which need not be of particularly high strength.

A further object is to provide an improved design as recited which is well adapted to be fabricated economically in a wide variety of customized sizes from a small number of different standardized and inherently economical structural components.

Still another object is to provide an improved sign as recited which is well suited to be effectively and most strongly attached to coacting support structure Without the necessity of incorporating into the sign structure itself either massive or particularly strong individual components.

A further object is to provide an improved sign structure as recited which is inherently capable of maintaining its characteristic free flowing permeability to the passage of wind through the sign structure under outdoor weather conditions, including icing conditions, the wind tunnels through the sign structure remaining effectively clear of clogging by ice.

Another object is to provide a roadway information display sign as recited in the preceding objects which is suitable for overhead use and adaptable for displaying messages on opposite sides to inform motorists approaching the sign from either of two generally opposite directions.

Other objects and advantages will become apparent from the following description of the exemplary'embodiments of the invention illustrated in the drawings, in which:

FIG. 1 is an elevational view showing a sign constructed in accordance with the invention and supported in a typical motorist informing position adjacent a traffic lane of a highway partially illustrated in section;

FIG. 2 is an elevational view on a substantially enlarged scale showing the visage of the sign presented to the oncoming motorist;

FIG. 3 is a vertical elevational view of the sign as viewed from the backside, with reference to FIG. 2;

FIG. 4 is a fragmentary sectional view of the sign and its support structure, on an enlarged scale, taken with reference to the line 4-4 of FIG. 3;

FIG. 5 is a fragmentary horizontal section view, on an enlarged scale, of the sign structure taken with reference to the line 55 of FIG. 3;

FIG. 6 is a more extensive vertical sectional view on an enlarged scale taken generally with reference to the line 6-6 of FIG. 3;

FIG. 7 is an elevational view of a sign constructed in accordance with the invention and modified to present messages on opposite sides to motorists approaching from opposite directions on roadways partially illustrated in section; and

FIG. 8 is a fragmentary horizontal sectional view of the sign structure of FIG. 7 taken with reference to the line 8-8 of that figure.

Referring now to the drawings in greater detail, the sign 20 illustrated in FIGS. 1 to 6 has been conceived by applicants invention for mounting in proximate relation to one or more traffic lanes 22 of a highway 24 in generally perpendicular relation to the traffic lanes to effectively display to approaching motorists essential messages concerning traffic and roadways ahead. Signs designed in accordance with the invention can be located overhead in relation to the nearest traffic lanes or they may be positioned alongside the roadway in proximate relation to adjacent traffic lanes 22 as shown.

As will presently appear, the construction of the sign 20 facilitates dimensioning of the sign to accommodate and effectively display a message of the complexity that is likely to be needed at the location along the highway where the sign is installed. Further, the construction of the sign facilitates quick and secure mounting of message lettering on the sign in straight rows by workmen following an utterly simple procedure requiring little or no skill. Moreover, the lettering can be replaced, repeatedly if desired, with equal ease and facility by lettering of different traffic and roadway messages.

The sign 20 comprises an upright rectilinear structure 26, light in weight as will presently appear, that defines a substantially flat and generally vertical sign face 28 which appears visually to the approaching motorist to be opaque and continuous. The position of the sign structure 26 in relation to the roadway 24 is such that the sign face 28 is disposed in a plane generally perpendicular to the direction of movement of vehicles along the nearest adjacent traffic lane 22.

The lettering of the roadway or traffic message 30, to be displayed to oncoming motorists, is mounted on the sign face 28 by fixing the individual letters 32 to a plurality of letter supports 34, FIGS. 2 and 6, which are shaped and bound together in spaced, parallel relation to each other in such manner that the overall sign structure 26 is generally pervious to the free flow of wind through the sign structure and the sign face 28 is caused to appear visually solid as perceived by an oncoming motorist approaching and passing along-side the sign. More particularly, the shape and mutual relationship of the letter supports 34 allow a generally free flow of wind through the sign structure, as will presently appear, while providing, in relation to the message lettering 32, a background surface 36 that is visually continuous as perceived by the motorist approaching and passing the sign along the traffic lane 22.

Preferably, the individual letter supports 34 are formed initially as continuous extrusions of aluminum or a suitable alloy of aluminum having a requisite resistance to corrosion in the environment where the sign is to be installed. The shaping of two typical letter supports 34 is illustrated in cross section in FIG. 5, the upper of the two letter supports shown in FIG. 5 being adapted, as will presently appear, to serve the additional function of providing an attachment for mounting the sign structure 26 on rearward support elements to be described.

In the sign structure 26, which is supported above the eye level of the approaching motorists as will be described, the letter supports 34 extend horizontally for substantially the full length of the sign structure 26 in vertically spaced relation to each other.

The several letter supports 34 have straight parallel marginal edges 38, which project forwardly, as best shown in FIGS. 5 and 6, into contiguous flush relation to the generally vertical sign face 28.

The projecting marginal edge of each letter support 34 defines a forwardly open horizontal groove 40 adapted to receive the threaded shanks of self-tapping screws 42, FIGS. 2 and 6, that function as attachments for removably yet securely fixing individual letters 32 of the message 30 in the message face 28.

Spaced apart in 'mutually parallel relation, the horizontal letter supports 34 inherently constitute convenient guides for placement of the letters 32 in straight lines on the message face 28. The spacing of theletter supports 34 is such that an individual letter 32 typically spans a plurality of adjacent letter supports 34, all of which support or back up the adjacent letter. The letter is secured by the attaching screws 42 to a sufficient number of underlying letter supports using an adequate number of screws to assure a firm and unfailing mount ing of the letter on the several underlying supports.

The individual letters 32 can be fashioned from any material deemed suitable for the purpose. A noncorrosive light metal or plastics material capable of withstanding outdoor weather conditions without deleterious effect can be used in fashioning the letters which are individually attached by screws as described.

The desired color and degree of light reflectivity of the letters 32'can be obtained by covering'the motorist confronting surfaces of the letters with a suitable surfacing material conforming to the specification and requisites demanded by highway engineers for driver information signs used in this service.

For future reference, it may be observed at this point that the placement of the parallel spaced letter support edges 38 with the screw-receiving grooves 40 opening forwardly in flush relation to the sign face 28 makes easy not only the initial procedure of. attaching the requisite lettering of a desired message to the sign face, using essentially a screwdriver, but makes replacement of the lettering with other lettering of a different message in the field equally easy and practical. The extensiveness of the cumulative linear length of thescrewreceiving grooves 40 affords practical assurance that the grooves will not be chewed up or rendered ineffective for firmly receiving and holding screws even in the event the message lettering ischanged repeatedly.

Rearwardlyof itsleading marginal edge 38, which is flush with the sign surface 28, each letter support 34 is laterally deflected in a common downward direction, as shown best in FIGS. 5 and 6, so that the letter supports 34 have, in relation to the lettersupportin'g marginal edges 38, lateral excursions 44 that approximate in their lateral extent at least the transverse width of the individual spacings 46 of the letter supports 34 from each other.

Thus, as shown best in FIGS. 5 and 6, the lateral excursions 44 of the respective letter supports 34 are inclined rearwardly and downwardly at an angle of approximately 42 relative to the horizontal, the downward extent of the excursions 44 being such that the lower rearportion of each letter support 34 overlaps somewhat, in a vertical sense, the leading forward edge 38 of the immediately underlying letter support. As a consequence, the oncoming motorist looking toward the sign and passing alongside the sign, which is mounted above eye level, sees the narrow leading edges of the letter supports 34 and the lower surfaces or undersides, denoted by the number 360, of the tiered letter supports 34.

The lower surfaces 360 of the several letter supports 34 appear visually to be continuous with the leading edges of the letter supports 34 and mutually overlap, as

perceived from a head-on or lower vantage point, to completely block vision through the sign structure and present the previously-mentioned background surface 36 for the message lettering 32. As explained, this background surface is perceived by the motorist as being continuous over the entire area of the message face 28.

In this connection, it will be appreciated that as the motorist approaches and passes the sign 20, which is located above eye level with reference to the traffic lane 22, the degree of overlap of the visually exposed undersides 360 of the tiered letter supports 34, with reference to the line of sight from the moving motorist to the message face 28, progressively increases with the consequence that the solid or continuous visage of the background surface 36 is maintained and even made more redundant by such increased visual overlap of the letter supports.

As will be referred to later, the letter supports 34 are inherently well suited to be produced most economically ancl satisfactorily as extrusions of aluminum or other suitable light metal material.

In'the highway service where the sign 20 is used, rigid and specific standards must be met regarding the color and reflectivity of the background surface for the traffic message lettering. These requisites for color and reflectivity can be easily met in the structure 26 by coating the undersides 360 and leading edges of the letter supports 34, if need be, with a coating material having the requisite color and reflectivity. In this connection, it should be appreciated that the background surface 36 actually perceived by the motorist is located for the most part on the undersides of the letter supports 34 where it is generally protected and shielded from descending pellets of precipitation, with the consequence that the newness and reflectivity of the surface are preserved and extended markedly in time.

The tiered letter supports 34 are firmly supported in mutually spaced parallel relation by a plurality of individual spacers 48 which are disposed between the letter supports in a plurality of stacks 50, The several stacks 50 of spacers 48 are themselves mutually spaced apart supports 34, FIG. 6.

along the letter supports as shown in FIG. 2, the succes sive spacers 48 ineach stack 50 being disposed in intervening relation between the vertically successive letter As viewed from the top, FIG. 4, each spacer 48 comprises a relatively thin central web 52 extending from front to back in relation to the sign structure 26 between a somewhat thickened vertical leading marginal edge 54 of the spacer and a similarly thickened vertical trailing marginal edge 56 of the spacer.

As viewed transversely in relation to the sign structure 26, and as seen in its longitudinal side levation, each spacer 48 stops somewhat short of the protruding leading and trailing marginal edges of the letter sup ports 34 and is shaped otherwise to conform to and define the previously-mentioned spacing 46 between the two adjacent letter supports. More particularly, the upper edge of each spacer 48 is shaped to conform to and fit against the overlying underside of the letter support immediately above, and the lower edge of each spacer 48 is similarly shaped to conform to and fit against the upper side of the underlying spacer 34.

In general outline, the form of each spacer 48, as viewed in longitudinal elevation may be envisioned as that of a modified parallelogram with opposite ends turning into parallel relation to each other.

At the bottom and top of each stack 50, a modified spacer 58, shaped as shown in FIG. 5, is placed against the outer surface of the outer letter support 38 to provide a generally fiat of squared surface 60 perpendicular to the stack. The modified spacer or cap 58 placed at each other end of each stack 50 is constructed similarly to the regular spacers 48, different from a regular spacer by being only slightly taller overall and having one longitudinal edge straight as shown rather than curved.

The spacers 48 and the intervening letter supports 34 in each stack 50 are securely bound together preferably by means of a pair of noncorrosive rods 62 which extend vertically through alined vertical holes 64, FIG. 4, in the forward and rearward enlarged marginal edges 54, 56 of the stacked spacers. The tie rods 62 pass through apertures 66, 68 in the intervening letter supports alined with the respective spacer holes 64. The several tie rods 62 project beyond the end spacers or caps 58 and are threaded at their outer ends to receive nuts 70 which are tightened to hold the interleafed spacers and letter supports firmly together.

The sign structure 26, thus formed, is light in weight yet at the same time extremely sturdy and strongly resistant to loads applied in any direction, including torsional loads. The inherent strength of the assembly is such that a structure of adequate strength can be provided, as will again be referred to, using individual components as-described which are relatively thin and light in weight by reason of their low volume as well as their being formed of light metal of low specific gravity.

For cosmetic reasons, the rectilinear assembly formed by the compressively bound letter supports 34 an spacers 48 is encircled by a peripheral border or frame 72 that can also be fashioned to advantage from a noncorrosive light metal. As shown in transverse section in FIGS. and 6, the border frame 72 is formed of an aluminum angle, also denoted by the number 72. Along the upper and lower sides of the structure 26, the border angle,72 has one leg 74 disposed in spanning relation to all the spacer stacks 50 to which the leg 74 is firmly clamped by the nuts 70 on the tie rods 62 which project out through the angle leg 74 as shown. A second or face leg 76 of the border angle 72 extends into overlapping relation to the letter support edge 38 of the adjacent outermost letter support 34 to which the border leg 76 is attached by screws 42 similar to those used in attaching the message letters 32. The inherent strength of the sign structure 26 is distributed rather evenly throughout the structure. Provision is made for attaching the sign structure 26 to strong supporting elements on the rearward side of the structure 26 in such manner that the supporting forces are widely distributed over the structure 26 with a consequent advantageous minimization and avoidance of destructive stress concentrations on the component elements of the sign structure where the supporting forces are supplied to the structure.

As shown best in FIGS. 3, 5 and 6, a small fraction of the letter supports 34 are specially shaped along their rear marginal edges to receive the heads of anchor bolts 80. In the construction illustrated, the rear marginal edge 82 of every sixth letter support 34 is enlarged and shaped, as best shown in FIG. 5, to define a rearwardly open T-slot 84 which is dimensioned and adapted to receive and anchor the heads of one or more anchor bolts 80 fitted into the slot.

In the example shown, the letter supports 34 are spaced vertically at 2 inch intervals and the letter supports specially shaped to define the T-slots 84 are spaced vertically at intervals of 1 foot. The thickness of the same sign structure 26 from the front edges to the rear edges of the letter supports 34 is about five inches.

Having reference to FIG. 3, the sign structure 26 is attached at its backside by a plurality of anchor bolts 80 to a diagonal brace 86 and is attached by other anchor bolts to two vertical support brackets 88, 90 having a generally 2" shape in cross section, FIG. 4, to a pair of vertical support columns or posts 92, 94 extending upwardly alongside the roadway 24 from permanent bases 96, 98.

The fact that the anchor bolts 80 may be located anywhere along the various anchoring slots 84 and used in any number desired permits powerful supporting force to be transmitted to the sign structure 26 in an evenly distributed fashion as illustrated with the avoidance of destructive stress concentrations on any of the components.

At this point, it should be appreciated that the leading letter support edges 38 of the letter supports 34 and the leading edges 54 of the stacked spacers 48 present cumulatively in the message face 28, which substantially covers the front of the sign structure 26, a frontal area which is only a very minor fraction of the overall area of the message face 28. As a consequence, the effective sail area and wind resistance of the sign structure 26 is reduced markedly to only a portion of the wind resistance of an impervious flat surface having an area equal to that of the message face 28.

The wind resistance of the sign structure 26 is reduced by the fact that differential wind pressure on the sign is relieved by air blowing through multitudinous wind tunnels extending from front to back through the entire structure. A wind tunnel 100 effective for relieving wind pressure on the sign is formed by each of the many spaces intervening between an adjacent pair of letter supports 34 and between adjacent stacks 50 of spacers 48 and by each of the spaces between the border 72 and the adjacent spacers 48 and supports 34.

As described, the leading marginal edges 38 of the several letter supports 34 project outwardly in mutually parallel relation. Thus, as shown and described, the

leading marginal edges 38 of the letter supports 38 are perpendicular to the sign face 28 and terminate in the sign face. Similarly, the rear marginal edges 102 of the letter supports 34, which are not formed to define anchor bolt channels 84, are shaped to project rearwardly beyond the spacers 48 in mutually parallel relation to each other and, as shown, in mutually parallel relation to the leading marginal edges 38 of the letter supports 34. The forwardly projecting frontal edges 38 of the letter supports 34 and the rearwardly projecting rear marginal edges 102 of the letter supports, all being mutually parallel tend to cause wind passing through the sign structure to leave the wind tunnels 100 in the same direction that the wind enters tunnels thus minimizing the airfoil action of the letter supports 34 on the wind. Aerodynamically, the letter supports may be regarded as louvers which function in the sign structure as described while allowing essentially free flow of air through the wind tunnels 100.

his also noteworthy that, even through the spacing and relationship of the letter supports or louvers 34 in relation to each other is such that vision through the sign structure is blocked by a continuous background surface 36 for the messagelettering 32 displayed to the motorist, the wind tunnels 100' by virtue of their size and the sweeping action of the air moving there through are not subject to clogging by ice or snow.

When located in overlying relation to the roadwa 24, the sign structure 26 is normally supported along its backside in the manner described by a suitable horizontal truss or the like which spans the roadway. The visually continuous background surface 36 in the sign structure shields the rearward supporting structure from sight so that the motorist sees only the message face 28. By virtue of itsinherentlightness in'weight and its low resistance towind,.the sign 20 can be extended in size as a practical matter to mask the entire length of its rearward supporting truss so that no trusswork is seen by the oncoming motorist. In other words, the wind spilling capability of the sign issuch that minimization of the area of the message face 28 for the purpose of reducing the wind loading is not a determinative factor in the design of practical signs with the consequence that the entire' structure of even long signs can be masked by the visually solid face .of the sign 20. It should be appreciated at this point that signs 20 of different size can be fashioned with ease from a very small number of different stock parts. The width of the sign is readily determinedby choosing the proper number of letter supports 34 and spacers 48, tying the stacks together with therods 62 that can be readily cut to any length. The letter supports 34 are extruded as stock items and can be easily cut to length to-determine the length of the sign structure. The letter supports which are specially fashioned to define the T-slots 84 are similarly cut to length from stock parts.

Component elements of the modified sign 20a incorporating the inventionand illustrated in FIG. 7 are identified by the same reference number with the addition of the suffix a." As shown,the sign 20a is located in the median strip 110 between traffic lanes 22a of a divided highway 24a.,

In this instance, the sign structure 26a is turned so that the letter supports 34a extend vertically rather than horizontally in parallel relation to eachother.

Moreover, the orientation of the letter supports 34a is such that the rearward excursions 44a of the letter supports 34a are deflected to the right in a rearward direction with reference to the oncoming motorist. When the letter supports 34a are disposed in vertical positions as illustrated, the. vision of motorists approaching the sign from opposite directions along the divided highway 24a is blocked so that no motorist approaching and passing alongside the sign can see through the sign structure. As a consequence, both sides of the sign structure 260 can be used for displaying traffic messages. i

To accommodate and support message lettering on opposite Sides of the sign structure 26a, both longitudinal edges of each letter support 34a are shaped to project outwardly and define screw-receiving grooves. For convenience, the marginal edges and screw-receiving grooves on one side of the sign are identified by the numbers 38a and 40a, respectively. The corresponding projecting edges and grooves of the letter supports appearing on the opposite side of the sign are identified by the numbers 38b and 40b, respectively.

Since both sides of the sign structure 26a serve to support and dispaly message lettering, the edges of the letter supports 34a are not available for defining anchor bolt slots such as the slots 84 forming a part of the previously-described sign 20. For this-reason, the peripheral frame or border 72a of the sign 20a is made sufficiently heavy and strong to function as an anchor for mounting brackets 1 12 such as shown in FIG. 8 that may be used to secure the sign frame 72a to support posts 92a, 94a or the like. The heavier peripheral frame 72a is supported on and attached to the core assembly of letter supports 34a and spacers 48a, as shown in FIG. 8 in generally the same manner that the border frame 72 is supported in the previously-described sign structure 26.

The invention is claimed as follows:

1. For displaying essential traffic and roadway information to motorists, a highway sign comprising an upright structure of rectilinear form defining a generally flat message face normally disposed in proximate generally perpendicular relation to a vehicular traffic lane in a generally vertical position above eye level, said structure comprising a plurality of generally horizontal letter supports disposed in spaced parallel relation to each other, each letter support having a forward letter support edge extending to said message face to support letters therein and defining a forwardly open groove shaped to receive removable letter attachment screws, a plurality of letter support spacers disposed between said letter supports in a plurality of stacks, said stacks of spacers being mutually spaced apart along the length of said letter supports with successive spacers in each stack disposed in intervening relation between successive letter supports, said letter supports extending rearwardly from said letter support edges thereof and being deflected laterally in a downward direction so that the letter supports have relative to the letter supportedges thereof sight blocking downward excursions that approximate at least the transverse width of the individual vertical spaces between successive letter supports, the letter supports having vertical thicknesses that are equal to only small fractions of the corresponding vertical: dimensions of the spaces intervening between successive letter supports and said spacers having transverse thicknesses that are equal to only small fractions of the corresponding spacings measured in the same direction between successive stacks of the spacers so that the letter supports and the spacers cumulatively define only a minor fraction of the frontal area of said message face and the spaces intervening between. the letter supports and the spacers form wind tunnels through which wind pressures on the upright structure are relieved, said sight blocking lateral excursions of the letter supports serving to eclipse vision through the wind tunnels and present a visually solid background surface for said message face with reference to a moving vantage point starting in front of said message face and passing the sign structure below the level of said message face thereof, a pair of tie rods extending through each stack of spacers and intervening letter supports to bind the spacers and letter supports together toform a strong torsion resistant structure, and a plurality of said letter supports having rear marginal edges enlarged and shaped to define support bolt receiving slots.

2. For displaying essential traffic and roadway information to motorists, a highway sign comprising an upright structure of rectilinear form defining a generally flat message face normally disposed in proximate generally perpendicular relation to a vehicular traffic lane in a generally vertical position above eye level, said structure comprising a plurality of generally horizontal letter supports disposed in vertically spaced parallel relation to each other, each letter support having a forward letter support edge extending to said message face to support therein letter characters having structural form and mass and being individually attachable to a plurality of the letter supports edges in spanning relation thereto, a plurality of letter support spacers disposed between said letter supports in a plurality of stacks, said stacks of spacers being mutually spaced apart along the length of said letter supports with successive spacers in each stack disposed in intervening relation between successive letter supports, said letter supports extending rearwardly from said letter support edges thereof and being deflected laterally in a downward direction so that the letter supports have relative to the letter support edges thereof sight blocking downward excursions that eclipse vision through said upright structure and present a visually solid background surface for said message face with reference to a moving vantage point starting in front of said message face and passing the sign structure below the level of said message face thereof, the letter supports having vertical thicknesses that are equal to only small fractions of the corresponding vertical dimensions of the spaces intervening between successive letter supports and said spacers having transverse thicknesses that are equal to only small fractions of the corresponding spacings measured in the same direction between successive stacks of the spacers so that the letter supports and the spacers cumulatively define only a minor fraction of the frontal area of said message face and the spaces, intervening between the letter supports and the spacers form wind tunnels through which wind pressures on the upright structure are relieved, and a plurality of said letter supports having rear marginal edges enlarged and shaped to define support receiving slots for supporting said upright structure in an elevated position outdoors, means binding together the stacked spacers and the intervening letter supports to form a strong lightweight structure.

3. For displaying driver information, a highway sign comprising an upright structure of rectilinear form defining a motorist confronting message face, said structure comprising a plurality of spaced parallel letter supports each having a forward letter support edge extending to said message face to support letters therein and being shaped to receive removable letter attachments, a plurality of letter support spacers disposed between said letter supports in a plurality of stacks, said stacks of spacers being mutually spaced apart along the length of said letter supports with successive spacers in each stack disposed in intervening relation between successive letter supports, said letter supports extending rearwardly from said letter support edges thereof and being deflected laterally in a common direction so that the letter supports have relative to the letter support edges thereof sight blocking lateral excursions that approximate at least the transverse width of the individual spaces between successive letter supports, the letter supports having transverse thicknesses that are equal to only small fractions of the corresponding transverse dimensions of the spaces intervening between successive letter supports and said spacers having transverse thicknesses that are equal to only small fractions of the corresponding spacings measured in the same direction between successive stacks of the spacers so that the letter supports and the spacers cumulatively define only a minor fraction of the frontal area of said message face and the spaces intervening between the letter supports and the spacers form wind tunnels through which wind pressures on the upright structure are relieved, said sight blocking lateral excursions of the letter supports serving to eclipse vision through the wind tunnels and present a visually solid background surface for said message face with reference to a moving vantage point starting in front of said message face and passing the sign structure at the side thereof toward which said sight blocking lateral excursions are deflected, and means binding together the spacers in each stack and the intervening letter supports to form therewith a strong torsion resistant structure.

4. For displaying essential traffic and roadway infor mation to motorists, a highway sign comprising an upright structure of rectilinear form defining a generally flat message face normally disposed in proximate generally perpendicular relation to a vehicular traffic lane in a generally vertical position above eye level, said structure comprising a plurality of generally horizontal letter supports disposed in vertically spaced parallel relation to each other, each letter support having a forward letter support edge extending to said message face to support therein letter characters having structural form and mass and being individually attachable to a plurality of the letter support edges in spanning relation thereto, means securing said letter supports in vertically spaced tiered relation to each other so that the letter supports define therebetween wind tunnels extending transversely through the upright structure to relieve wind pressure thereon, said letter supports extending rearwardly from said letter support edges thereof and being deflected laterally in a downward direction so that the letter supports have relative to the letter support edges thereof sight blocking downward excursions that eclipse vision through said wind tunnels and present a visually solid background surface for said message face, and a plurality of said letter supports having rear marginal edges enlarged and shaped to define support receiving slots for supporting said upright structure in an elevated position outdoors.

5. For displaying essential traffic and raodway information to motorists, a highway sign comprising an upright structure defining a generally flat message face normally disposed proximate generally perpendicular relation to a vehicular traffic lane in a generally vertical position, said structure comprising a plurality of spaced generally parallel letter supports, said respectiveletter supports having forward letter support edges projecting forwardly in mutually parallel relation to each other and to said message face to support message letter characters in said message face, said forwardly projecting letter support edges defining forwardly open grooves for receiving letter attached screws for attachment of individual letter characters to the letter supports in said message face, means securing said letter supports in spaced parallel relation to each other so that the letter supports define therebetween wind tunnels extending transversely through the upright structure to relieve wind pressure thereon, said letter supports extending rearwardly from said letter support edges thereof and being deflected laterally in a common direction so that the letter supports have relative to the letter support edges thereof sight blocking excursions that eclipse vision through said wind tunnels and present a visually solid background surface for said message face, a plurality of the letter supports having rear marginal edges enlarged and shaped to define support bolt receiving slots, and the remainder of said letter supports for the most part having rear marginal edges projecting rearwardly in mutually parallel relation to said forward edges of the letter supports.

6. For displaying essential traffic and roadway information to motorists, a highway sign comprising an upright structure of rectilinear form defining on the forward side thereof a generally flat message face normally disposed in proximate generally perpendicular relation to a vehicular traffic lane in a generally vertical position, said structure comprising a plurality of elongated letter supports parallel to said flat message face, letter support spacing means positively coacting with said letter supports to hold the latter immovably in mutually spaced relation to define therebetween wind tunnels extending from the message face through said upright structure in a common direction away from the message face to relieve the pressure of wind on the structure, each letter support having a forward marginal edge of substantial width extending forwardly to said message face in generally perpendicular relation thereto to support letters therein and being shaped to receive removable letter attachments, said letter supports extending rearwardly from said forward marginal edges thereof and being deflected laterally in a common direction so that the letter supports have relative to the forward letter supporting edges thereof sight blocking lateral excursions that approximate at least the transverse width of the individual wind tunnels between successive letter supports, the letter supports having transverse thicknesses that are equal to only small fractions of the corresponding transverse dimensions 'of the wind tunnels intervening between successive letter supports and said letter support spacing means having a cumulative thickness measured longitudinally with respect to the letter supports that is equal to only a small fraction of the corresponding cumulative dimension measured in the same direction of the individual tunnels so that the letter supports and the letter support spacing means together define only a very minor fraction of the frontal area of said message face with the remaining portion of the frontal area of said message face being defined by the open forward ends of said wind tunnels which are generally perpendicular to said message face, said sight blocking lateral excursions of the letter supports serving to eclipse vision through the wind tunnels and present a visually solid background surface for said message face with reference to a moving vantage point starting in front of said message face and passing the sign structure at the side thereof toward which said sight blocking lateraly excursions are deflected, and said respective letter supports having at the rear side of said structure mutually parallel rear marginal edges of substantial width extending rearwardly in generally parallel relation to said forward edges of the letter supports whereby the forward and rear marginal edges of the letter supports tend to cause wind to enter and leave said wind tunnels in parallel planes generally perpendicular to said struc- 

1. For displaying essential traffic and roadway information to motorists, a highway sign comprising an upright structure of rectilinear form defining a generally flat message face normally disposed in proximate generally perpendicular relation to a vehicular traffic lane in a generally vertical position above eye level, said structure comprising a plurality of generally horizontal letter supports disposed in spaced parallel relation to each other, each letter support having a forward letter support edge extending to said message face to support letters therein and defining a forwardly open groove shaped to receive removable letter attachment screws, a plurality of letter support spacers disposed between said letter supports in a plurality of stacks, said stacks of spacers being mutually spaced apart along the length of said letter supports with successive spacers in each stack disposed in intervening relation between successive letter supports, said letter supports extending rearwardly from said letter support edges thereof and being deflected laterally in a downward direction so that the letter supports have relative to the letter support edges thereof sight blocking downward excursions that approximate at least the transverse width of the individual vertical spaces between successive letter supports, the letter supports having vertical thicknesses that are equal to only small fractions of the corresponding vertical dimensions of the spaces intervening between successive letter supports and said spacers having transverse thicknesses that are equal to only small fractions of the corresponding spacings measured in the same direction between successive stacks of the spacers so that the letter supports and the spacers cumulatively define only a minor fraction of the frontal area of said message face and the spaces intervening between the letter supports and the spacers form wind tunnels through which wind pressures on the upright structure are relieved, said sight blocking lateral excursions of the letter supports serving to eclipse vision through the wind tunnels and present a visually solid background surface for said message face with reference to a moving vantage point starting in front of said message face and passing the sign structure below the level of said message face thereof, a pair of tie rods extending through each stack of spacers and the intervening letter supports to bind the spacers and letter supports together to form a strong torsion resistant structure, and a plurality of said letter supports having rear marginal edges enlarged and shaped to define support bolt receiving slots.
 2. For displaying essential traffic and roadway information to motorists, a highway sign comprising an upright structure of rectilinear form defining a generally flat message face normally disposed in proximate generally perpendicular relation to a vehicular traffic lane in a generally vertical position above eye level, said structure comprising a plurality of generally horizontal letter supports disposed in vertically spaced parallel relation to each other, each letter support having a forward letter support edge extending to said message face to support therein letter characters having structural form and mass and being individually attachable to a plurality of the letter support edges in spanning relation thereto, a plurality of letter support spacers disposed between said letter supports in a plurality of stacks, said stacks of spacers being mutually spaced apart along the length of said letter supports with successive spacers in each stack disposed in intervening relation between successive letter supports, said letter supports extending rearwardly from said letter support edges thereof and being deflected laterally in a downward direction so that the letter supports have relative to the letter support edges thereof sight blocking downward excursions that eclipse vision through said upright structure and present a visually solid background surface for said message face with reference to a moving vantage point starting in front of said message face and passing the sign structure below the level of said message face thereof, the letter supports having vertical thicknesses that are equal to only small fractions of the corresponding vertical dimensions of the spaces intervening between successive letter supports and said spacers having transverse thicknesses that are equal to only small fractions of the corresponding spacings measured in the same direction between successive stacks of the spacers so that the letter supports and the spacers cumulatively define only a minor fraction of the frontal area of said message face and the spaces intervening between the letter supports and the spacers form wind tunnels through which wind pressures on the upright structure are relieved, and a plurality of said letter supports having rear marginal edges enlarged and shaped to define support receiving slots for supporting said upright structure in an elevated position outdoors, means binding together the stacked spacers and the intervening letter supports to form a strong lightweight structure.
 3. For displaying driver information, a highway sign comprising an upright structure of rectilinear form defining a motorist confronting message face, said structure comprising a plurality of spaced parallel letter supports each having a forward letter support edge extending to said message face to support letters therein and being shaped to receive removable letter attachments, a plurality of letter support spacers disposed between said letter supports in a plurality of stacks, said stacks of spacers being mutually spaced apart along the length of said letter supports with successive spacers in each stack disposed in intervening relation between successive letter supports, said Letter supports extending rearwardly from said letter support edges thereof and being deflected laterally in a common direction so that the letter supports have relative to the letter support edges thereof sight blocking lateral excursions that approximate at least the transverse width of the individual spaces between successive letter supports, the letter supports having transverse thicknesses that are equal to only small fractions of the corresponding transverse dimensions of the spaces intervening between successive letter supports and said spacers having transverse thicknesses that are equal to only small fractions of the corresponding spacings measured in the same direction between successive stacks of the spacers so that the letter supports and the spacers cumulatively define only a minor fraction of the frontal area of said message face and the spaces intervening between the letter supports and the spacers form wind tunnels through which wind pressures on the upright structure are relieved, said sight blocking lateral excursions of the letter supports serving to eclipse vision through the wind tunnels and present a visually solid background surface for said message face with reference to a moving vantage point starting in front of said message face and passing the sign structure at the side thereof toward which said sight blocking lateral excursions are deflected, and means binding together the spacers in each stack and the intervening letter supports to form therewith a strong torsion resistant structure.
 4. For displaying essential traffic and roadway information to motorists, a highway sign comprising an upright structure of rectilinear form defining a generally flat message face normally disposed in proximate generally perpendicular relation to a vehicular traffic lane in a generally vertical position above eye level, said structure comprising a plurality of generally horizontal letter supports disposed in vertically spaced parallel relation to each other, each letter support having a forward letter support edge extending to said message face to support therein letter characters having structural form and mass and being individually attachable to a plurality of the letter support edges in spanning relation thereto, means securing said letter supports in vertically spaced tiered relation to each other so that the letter supports define therebetween wind tunnels extending transversely through the upright structure to relieve wind pressure thereon, said letter supports extending rearwardly from said letter support edges thereof and being deflected laterally in a downward direction so that the letter supports have relative to the letter support edges thereof sight blocking downward excursions that eclipse vision through said wind tunnels and present a visually solid background surface for said message face, and a plurality of said letter supports having rear marginal edges enlarged and shaped to define support receiving slots for supporting said upright structure in an elevated position outdoors.
 5. For displaying essential traffic and roadway information to motorists, a highway sign comprising an upright structure defining a generally flat message face normally disposed in proximate generally perpendicular relation to a vehicular traffic lane in a generally vertical position, said structure comprising a plurality of spaced generally parallel letter supports, said respective letter supports having forward letter support edges projecting forwardly in mutually parallel relation to each other and to said message face to support message letter characters in said message face, said forwardly projecting letter support edges defining forwardly open grooves for receiving letter attached screws for attachment of individual letter characters to the letter supports in said message face, means securing said letter supports in spaced parallel relation to each other so that the letter supports define therebetween wind tunnels extending transversely through the upright structuRe to relieve wind pressure thereon, said letter supports extending rearwardly from said letter support edges thereof and being deflected laterally in a common direction so that the letter supports have relative to the letter support edges thereof sight blocking excursions that eclipse vision through said wind tunnels and present a visually solid background surface for said message face, a plurality of the letter supports having rear marginal edges enlarged and shaped to define support bolt receiving slots, and the remainder of said letter supports for the most part having rear marginal edges projecting rearwardly in mutually parallel relation to said forward edges of the letter supports.
 6. For displaying essential traffic and roadway information to motorists, a highway sign comprising an upright structure of rectilinear form defining on the forward side thereof a generally flat message face normally disposed in proximate generally perpendicular relation to a vehicular traffic lane in a generally vertical position, said structure comprising a plurality of elongated letter supports parallel to said flat message face, letter support spacing means positively coacting with said letter supports to hold the latter immovably in mutually spaced relation to define therebetween wind tunnels extending from the message face through said upright structure in a common direction away from the message face to relieve the pressure of wind on the structure, each letter support having a forward marginal edge of substantial width extending forwardly to said message face in generally perpendicular relation thereto to support letters therein and being shaped to receive removable letter attachments, said letter supports extending rearwardly from said forward marginal edges thereof and being deflected laterally in a common direction so that the letter supports have relative to the forward letter supporting edges thereof sight blocking lateral excursions that approximate at least the transverse width of the individual wind tunnels between successive letter supports, the letter supports having transverse thicknesses that are equal to only small fractions of the corresponding transverse dimensions of the wind tunnels intervening between successive letter supports and said letter support spacing means having a cumulative thickness measured longitudinally with respect to the letter supports that is equal to only a small fraction of the corresponding cumulative dimension measured in the same direction of the individual tunnels so that the letter supports and the letter support spacing means together define only a very minor fraction of the frontal area of said message face with the remaining portion of the frontal area of said message face being defined by the open forward ends of said wind tunnels which are generally perpendicular to said message face, said sight blocking lateral excursions of the letter supports serving to eclipse vision through the wind tunnels and present a visually solid background surface for said message face with reference to a moving vantage point starting in front of said message face and passing the sign structure at the side thereof toward which said sight blocking lateraly excursions are deflected, and said respective letter supports having at the rear side of said structure mutually parallel rear marginal edges of substantial width extending rearwardly in generally parallel relation to said forward edges of the letter supports whereby the forward and rear marginal edges of the letter supports tend to cause wind to enter and leave said wind tunnels in parallel planes generally perpendicular to said structure. 